Photo-alignment films have excellent characteristics, namely, the films are free of very small scratches introduced by mechanical rubbing, dusting due to rubbing, and the risk of breaking of a TFT element, which may accompany the dusting, and enable high-definition patterning. For this reason, the films have been applied energetically to various liquid crystal displays. The demand for photo-alignment films for the horizontal alignment (planar alignment) used for IPS/FFS displays is particularly enormous.
In a general method for producing a photo-alignment film without a rubbing treatment, a solution containing a photo-alignment polymer is first applied onto a substrate to form a dried coating film, and then the ability of controlling the alignment of liquid crystals is given to the surface of the photo-alignment film by applying polarized light to the coating film (for example, see PTL 1).